EP2220748A2

EP2220748A2 - Method for producing a stator housing unit

Info

Publication number: EP2220748A2
Application number: EP08862858A
Authority: EP
Inventors: Jörg NELGES; Thomas Gilke
Original assignee: ABB Technology AG
Current assignee: ABB Technology AG
Priority date: 2007-12-15
Filing date: 2008-12-05
Publication date: 2010-08-25
Also published as: CN101897103A; US20100277031A1; WO2009077088A2; DE102007060654A1; WO2009077088A3

Abstract

The invention relates to a method for producing a stator housing unit (20) for an electric machine, wherein a stator (12, 22) is connected to a housing (14, 24). Before connecting, at least one partial surface of the common contact surfaces is coated with a paint material comprising a material additive expanding irreversibly upon first reaching a prescribed expansion temperature. The invention further relates to a stator housing unit (20) and a paint material having 5% to 10% weight proportion of a material additive expanding irreversibly upon first reaching a prescribed expansion temperature, 10% to 20% boron nitride, and phenolic resin.

Description

description

The invention relates to methods for manufacturing a stator-housing unit for an electric machine, wherein a stator is connected to a housing, a stator housing unit and a paint material.

It is well known that electric machines such as asynchronous motors or generators have a stator. Such a stator usually contains layered laminations with grooves for winding conductors, which are introduced during the manufacturing process of the electric machine.

A stator is usually connected during the manufacturing process of an electric machine with a housing surrounding him or added to this. Such a housing is used for example for mechanical protection of the manufactured electric machine but also for their better handling. It is for example possible to provide fasteners on the housing, which facilitate the subsequent assembly of the electrical machine.

It is further known that electrical machines heat up during their operation due to electrical losses, which heat loss is derived from the electrical machines for thermal reasons. Such heating occurs in particular in the electrical winding conductors and leads to the heating of these surrounding components, which ultimately heat energy via an outer interface of the electrical machine to the environment. A component which has a high proportion of the outer boundary surface of the electrical machine is the housing thereof. This may for example also be provided with cooling fins, in order to achieve a desired increased heat release capability by the associated increase in the outer boundary surface.

The disadvantage is that even after the joining of stator and housing due to the manufacturing technology necessary clearance fits between the stator and the housing are present, which adversely affect the heat transfer between the winding conductors and outer interface. Depending on the size or power of the electrical machine, the length of such a necessary manufacturing distance is typically in the range of 0.1 mm to 2 mm, the power of corresponding electrical machines being between a few kW and several 100 MW.

Based on this prior art, it is an object of the invention to provide a method and means for producing a stator housing unit, with which the thermal conductivity between the stator and the housing is improved or a corresponding stator housing unit.

This object is achieved by a method of the type mentioned.

Accordingly, the method for producing a stator housing unit for an electrical machine is characterized in that before joining the stator and housing at least a partial surface of the common contact surfaces is coated with a paint material, which is an irreversibly expanding upon first reaching a certain expansion temperature addition of material and that the connected stator-housing unit is heated to at least the expansion temperature.

Thus, it is possible in an advantageous manner, volumes between connected stator and housing, which result from the manufacturing process necessary for the connection clearance fit, with a solid expansion material of ge to fill with air of increased thermal conductivity. The expansion material also has the advantage that the mechanical connection between the stator and the housing is further increased by filling in the volumes.

In a further embodiment of the method according to the invention, a paint material based on phenolic resin is used with the material additive mentioned above and with a further proportion of boron nitride.

It has been shown that boron nitride advantageously increases the thermal conductivity of a phenolic resin-based paint material. Thus, the thermal conductivity between stator and housing can be further increased.

Particularly advantageous is a variant of the method according to the invention, in which a phenol resin-based paint material with 5% -10% by weight of the first time reaching an expansion temperature irreversibly expanding material additive and 10% -20% boron nitride is used. The details of the proportions by weight relate in each case to the liquid state of the paint material.

In a further embodiment of the method according to the invention, the stator is connected to the housing only after a predetermined minimum time after coating of the stator and / or housing.

In this way, the applied lacquer layer dries before connecting in an advantageous manner and the connection process can be further simplified.

The object of the invention is also achieved by a stator housing unit for an electrical machine, which is characterized in that on at least a partial surface of the contact surface between the stator and the housing, a paint material is present, which is irreversibly expanded after first reaching a certain expansion temperature addition of material having.

Manufacturing-related based on a gap between the stator and housing volumes are filled with expansion material in an advantageous manner. As a result, a particularly high thermal conductivity between the stator and the housing is achieved. The object according to the invention is furthermore achieved by a paint material based on phenol resin with 5% to 10% by weight of a material additive which irreversibly expands when an expansion temperature is reached for the first time and 10% to 20% boron nitride. The details of the proportions by weight relate in each case to the liquid state of the paint material. In the dried state of the phenol resin-based paint material provided with material additive, ie after the volatile constituents have escaped, other proportions by weight of the material additives result, which amount to about 12.5 to 25% by weight of the material additive irreversibly expanding when an expansion temperature is first reached and about 25%. to 50% boron nitride.

It has been found that this composition is particularly suitable for achieving the stated object.

As an irreversibly expanding material additive, for example, the product .Expancel 'type 950 DU 120 AKZO Nobel. "Expancel" is characterized by the fact that in a gas-tight, only a few microns large plastic cover a precisely measured amount of a propellant is included. When this microsphere is heated or heated, the plastic shell softens, the propellant becomes gaseous and the microsphere expands irreversibly in a defined manner. But there are also other material additives with similar properties conceivable, including those that work on other principles of action, such as expansion due to chemical processes.

As a suitable boron nitride, for example, the products of the company Boron Nitride Momentive Performance Materials type BN5 or CF100 have proven.

A suitable phenolic resin is, for example, the product LG 9968 from Hexion / Bakelite.

Reference to the embodiments illustrated in the drawings, the invention, further embodiments and other advantages will be described in detail. Show it:

1 shows a first overview image with a separate coated first stator and a first housing FIG. 2 shows a second overview image with a connected stator-housing unit

1 shows a first overview image 10 of a separate first stator 12 and of a first housing 14 of an electrical machine. Both the stator 12 and the housing 14 are indicated in an idealized form as rotationally symmetrical about an axis of rotation 30. According to the invention, electric machines in the power range of a few kW up to several 100 MW are conceivable.

The stator 12 has an outer diameter 13, which is smaller than the inner diameter 15 of the housing, wherein the design match of inner diameter 15 to outer diameter 13, for example in the range of 0.2mm to 4mm, resulting in distances between stator and housing of 0.1 mm to 2mm. The stator 12 is coated on its outer circumferential surface with a lacquer layer 16 which has a thickness 17 and has not yet been heated to an expansion temperature and has a thickness of, for example, 0.05 to 1 mm. Due to any unevenness of the outer surface of the stator 12 and tolerances in the coating process, the thickness 17 of the lacquer layer 16 may vary.

Before connecting stator 12 and housing 14, first the later common contact area of stator 12 and housing 14 is to be completely or partially coated with a paint material according to the invention. The contact surface is formed by the outer circumferential surface of the stator 12 and the inner circumferential surface of the housing 14. Accordingly, at least one of the two mentioned surfaces forming the contact surface is to be painted in the area of the later contact surface at which the thermal conductivity between the stator 12 and the housing 14 is to be improved. In Fig. 1, a coated stator 12 is shown while the housing 14 is uncoated. Depending on the size and power of the electric machine, the average thickness of the paint layer is in the range of 50 .mu.m to 600 .mu.m in the air-dried state, ie after the lapse of a certain time interval after the coating process. Immediately after the coating process, the thickness of the lacquer layer in the so-called wet state is higher, for example by a factor of 1, 5 to 4. This reduction of the layer thickness is based on the fact that volatile constituents are contained in the lacquer material which evaporate during the time interval. A suitable time interval is in the range of 10 minutes to 2 hours, depending on the layer thickness, ambient temperature conditions, composition of the paint material and other influencing factors.

Stator 12 and housing 14 are subsequently pushed into each other, which is indicated in the figure by a directional arrow 18.

FIG. 2 shows a second overview image of a stator housing unit 20 with a second stator 22 and a second housing 24. The space between the second stator 22 and the second housing 24 is completely filled with a lacquer layer which, after being connected, already heated to expansion temperature has been. During the heating process, a volume expansion of the lacquer layer took place, which filled up any air volumes. Due to the complete filling of the intermediate space, an additional mutual mechanical fixation of stator and housing takes place in an advantageous manner.

Particularly favorable properties are achieved, in particular, by using a coating material with 5% to 10% by weight of a material additive that irreversibly expands when an expansion temperature is reached for the first time, 10% to 20% of boron nitride and phenolic resin. The boron nitride improves the thermal conductivity in this case.

In the event that the theoretical expansion volume of the coated paint material exceeds the volume to be filled between the stator and housing, the expansion process stops due to the associated pressure increase, especially in the above-mentioned paint material independently. 6a

LIST OF REFERENCES

first overview image separate first stator and first housing first stator outer diameter first stator first housing inner diameter first housing first paint layer thickness first paint layer movement direction when connecting second overview image stator housing unit second stator second housing second paint layer rotation axis

Claims

claims

A method of manufacturing a stator-housing unit (20) for an electrical machine, wherein a stator (12, 22) is connected to a housing (14, 24), characterized in that at least a part of the common surface is connected before joining Contact surfaces is coated with a paint material having an irreversibly expanding upon first reaching a certain expansion temperature addition of material, and that the connected stator housing unit (20) is heated to at least the expansion temperature.

2. The method according to claim 1, characterized in that a paint material based on phenolic resin is used with a proportion of boron nitride for the coating.

3. The method according to claim 1, characterized in that is used as the coating, a paint material based on phenolic resin with 5% -10% by weight of the first time reaching an expansion temperature irreversibly expanding material additive and 10% -20% boron nitride.

4. The method according to any one of the preceding claims, characterized in that the stator (12, 22) after a predetermined minimum time after coating with the housing (14, 24) is connected.

5. Stator housing unit (20) for an electrical machine, characterized in that on at least a partial surface of the contact surface between the stator (12, 22) and housing (14, 24) a paint material is present, which after a first reaching a has certain expansion temperature irreversibly expanded material additive.

6. paint material based on phenolic resin with 5% to 10% by weight of an irreversibly expanding upon first reaching an expansion temperature addition of material and 10% to 20% boron nitride.